Can Cats Eat Onions?

Can cats eat onions? I love onions more than anything. A hamburger is not a hamburger without onions. I love them so much I often ask for extra onions on my sub sandwiches. They are also delicious to any stew, soups, and sauces. In most kitchens they are a staple vegetable. For this reason, it is important to know if cats can eat onions. While onions are tasty for humans, they are not for our fur babies. So, can cats eat onions? The answer is no. 

Another important consideration is the difference between raw onions and cooked onions, or things like onion powder and dehydrated onions. 

Why Can't Cats Eat Onions?

Onions belong to the Allium species of plants. All Allium species are toxic to cats. This includes onions, garlic, chives, shallots, leeks and scallions. So to make this clear, cats cannot eat onion and garlic. 

The Allium specie contain chemicals called organosulfoxides, which upon chewing convert to sulfur-containing compounds. This is what gives allium plants an enjoyable aromatic flavor. However, for cats these compounds damage red blood cells resulting in the cells not being able to carry oxygen to the brain. This can cause anemia, liver damage and even death.

How Much onion Can a Cat Accidentally Eat?

Even a small amount of onion can be dangerous to cats. Consumption of as little 5 grams of onion can result in changes in the blood. Toxicosis normally occurs if the animal ingests 0.5 percent of their body weight. It is best if your cat does not consume any onion at all to avoid the risk of health issues.

Can Cats Eat Onions That Are Raw? Can Cats Eat Onions That Are Cooked?

So what is the difference of raw vs. cooked onions? The most dangerous are raw onions, then dehydrated, then cooked. All onion in all forms are dangerous to cats. However, cats generally are not tempted to eat raw onions. Cats usually get exposed to onions from cooked and processed human foods. In many processed foods onions are a frequent additive, therefore it is not advised to share human foods with you cat unless you check the ingredients carefully. 

What to Do if Your Cat Eats Onion

The first signs of onion toxicosis is vomiting and diarrhea. Onion toxicity will cause oxidative damage to red blood cells, making the red blood cells more likely to rupture. It also causes gastroenteritis resulting in nausea, oral irritation, drooling, abdominal pain, vomiting and diarrhea. Other clinical signs include lethargy, pale gums, increased heat rate, increased reparatory rate, weakness, exercise intolerance and collapse. The poisoning may also have a delayed onset and clinical signs may not occur for several days. 

If your cat is vomiting or has diarrhea, seek veterinarian assistance immediately. Onion poisoning can be treated. 

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